1. Field of the Invention
This invention relates generally to a method and apparatus for recording and/or reproducing digital data on/from slant tracks of a tape recoding medium and, more particularly, is directed to a method and apparatus for recording and/or reproducing digital data with error correction codes.
2. Description of the Prior Art
A digital video tape recorder (VTR) in which a video signal is recorded on and reproduced from slant tracks of a magnetic tape is known and one of recording formats of the digital VTR is disclosed in Japanese laid open patent publication No. 40573/85. In such digital VTR, each field of a television signal is analog-to-digital converted and the digital data is recorded on four consecutive slant tracks of the magnetic tape.
First redundancy symbols each of eight bits for an outer error correction code are generated from a first predetermined number of symbols each of eight bits and constitute an outer error correction block together with the first predetermined number of symbols. Second redundancy symbols each of eight bits for an inner error correction code are generated from a second predetermined number of symbols which are taken from the shuffled symbols in the outer error correction code blocks and constitute an inner error correction block together with the second predetermined number of symbols.
In the beginning portion of the slant track where the reproducing head starts tracing the track, the reproducing signal is not obtained reliably so that digital data is not extracted with complete accuracy and may in fact contain many errors. Specifically, in special reproducing modes such as operation with track jumping by a dymamic tracking head, the reproducing head traces every several tracks intermittently, so that relatively long burst errors occur in the reproduced data, the length of which exceeds the error correction ability of the inner code and outer code. Such errors remain uncorrected.